Contact
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Welcome to my personal homepage! If you are here to use the X-ray source quick viewer that I create for the Chandra and XMM-Newton source catalogs, please click here.
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Research Scientist
Institute for the Study of Earth,
Oceans, and Space
245A Morse Hall
University of New Hampshire
8 College Road
Durham, NH 03824-2600
U.S.A.
dacheng@dachenglin.com
www.dachenglin.com
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Educational Background:
- 2009 Ph.D. - Physics, Massachusetts Institute of Technology
- 2003 B.S. - Geophysics, University of Science and Technology of China
Research Interests:
- The accretion process in neutron-star low-mass X-ray binaries and properties of dense matter
- Fast variability such as quasi-periodic oscillations
- The accretion process around black holes across mass scale: black-hole X-ray binaries, ultra-luminous X-ray sources, AGN
- The evolution of AGN
- Tidal disruption events (Tidal disruption of stars by dormant supermassive black holes)
- Catalog studies
Recent News: ****Black Hole Meal Sets Record for Duration and Size - A supermassive black hole in a small galaxy 1.8 billion light years away has been partaking in a decade-long binge of a star.
- This is known as a tidal disruption event and happens when an object gets too close to a black hole and is torn apart by gravity.
- Other similar events have been seen before but this one is much longer, representing an unusually massive meal.
****A Wandering Massive Black Hole Caught Shredding a Star
Within this optical light image from the Hubble Space Telescope, the massive black hole and its host galaxy are in the box in the upper left. The inset on the left is a close-up view of the galaxy, with what may be the source associated with this black hole circled. The inset on the right is Chandra’s X-ray image of the massive black hole.
More information, click here. The paper can be found here.
***Strong Heartbeat-Like Signals from Gorging Supermassive Black Hole
The XMM-Newton space observatory from European
Space Agency detected an extremely rare heartbeat-like X-ray pulsation
signal from a black hole of 100,000 times that of the
sun at the center of a galaxy at a distance of 1.7 billion light years.
The black hole was gorging on matter at the highest possible rate. Such
signals are common in small black holes with mass less than 20 times
that of the sun, but are very rare among supermassive black holes. Only
two cases were reported before, but with much weaker signals.
The pulse rate is once per 3.8 hours (see the figure above), much lower
than those in small black holes, just like smaller animals have higher
heart rates!
More information, click here. The paper can be found here.
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